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MATERIAL HANDLING—TRANSPORTATION OF SOLIDS
107
Example of Net Operating Costs.—Required the net operating cost per ton of a 10-in. suction conveyor handling 7,500 tons of ashes per year, power commanding a value of 3 cts. per horsepower delivered at the exhaust fan drive. Ashes weigh 45 Ib. per cubic foot.
Capacity of conveyor:
W = 0.385 X 45 X 10 X 10 = 17.325 say, 15 tons per hour.
Horsepower requirements:
Horsepower =0.55 X 10 X'10 = 55 Costs:
RCis = 143.7 X 10 X 10 = 14,370
Take market price at 25 per cent above relative cost. 14,370 - 17,962.5—say $18,000.
Fixed charges:     (0.085 X 18,000)...................... $1,530.00
Power charge:   ' (0.03 X 55 X 500).....................        825.00
Supply expense: (0.01 X 55 X 500).....................        275.00
Depreciation:       (0.10 X 18,000).......................<    1,800.00
Formula (29)
Formula (30)
Formula (31) Initial cost = 1.25 X
Net operating cost: (4,430/7,500)
WEIGHTS OF CERTAIN SOLIDS
$4,430.00 $0.59 per ton
Substance	Average sp." gr. water = 1	Average weight Ib. per cu. ft.
Asbestos rock	3 2	200
Ashes (packed)              ........	0 72	45
Asphalt ......       .................	1 1-1 8	68-100
Bone	1 7-2 0	106-125
Brick (hard)	2 0-2 4	125-150
Brick (fire)      .............       .   .	2 25-2 4	140-150
Brick soft ...........................	1.5-1 7	93-106
Cement, loose ........................	1.3-2.0	81-125
Chalk	2 5	156
Charcoal     .          . .         ....        ....	.28-. 57	17-35
Clay ..........................	1.8-2.6	112-162
Coal anthracite	1 3-1 7	81-106
Coal bituminous	1 2-1.5	75-94
Coke solid               .           ...       ....	1.0-1.7	62-106
Coke loose piled		20-30
Corundum	39-40	243-249
Dolomite	2 8	177
Earth, dry		76-95
Earth, moist           ..................		78-98
Feldspar. . .          ...................	2.55-2.75	159-172
Flint	2 6	162
Gas carbon	1 88	117
Granite   .                       ...	2.56-2.88	159-189
Graphite               ................	2.26	141
Gravel ......         ..................	1.6-1.9	100-120